Trimming-machine.



H. T. isLAcKwuL, TRIMMING MACHINE- APPLICATION FILED MAY 23vl9l1.

Patenbd Dec.3,1918.

F E g TBIMMIIilG-MACHINE.

Specification of Letters Patent.

Application filed May 28, 1917. Serial No. 171,447.

To all whom it may concern:

Be it known that I, HARRY T. BLACKWELL, a citizen of the United States, residing at Brockton, in the county of Plymouth and State of Massachusetts, have invented certain Improvements in Trimming-Machines, of which the following description, in connection with the accompanying drawings, is

a specification, like reference characters on the drawings indicating like parts in the several figures.

This invention relates to rotary trimming machines, and in particular to machines used. to trim the edges of the soles of shoes.

The cutters used in these machines are rotated at very high speed, for example, 7300 R. P. M It is necessary that parts rotating at such speed be very accurately balanced in order to avoid vibration, and this is especially necessary in a sole edge trimming machine since these machines have been found to be exceedingly sensitive to vibration, which causes a wavy effect to appear in the trimming.

The operator presents the shoe t the cut ter with his fingers along the sol new the edge, in order to steady it properly, and moves the sole edge over the cutter. It is necessary to protect his finger from the ends of the cutter teeth and this is done by a sleeve which encircles the shaft, fits up against the base of the cutter and is of slightly larger diameter than the base of the cutter. The operator may rest his finger against this sleeve with safety.

It has been a custom in the past to mount this sleeve on the rotating shaft. which it was very likely to throw out of balance, and

the balancing of the sleeve and shaft to permit rotation without vibration at the high speed mentioned, was a very troublesome matter. It was also necessary to make the sleeve adjustable longitudinally of the shaft in order to adapt it to use with cutters of different thicknesses, and the construction required in order to obtain this advantage aggravated the problem of balancing.

A further difiiculty is met with in these machines, which pre udices the accuracy of the operation they perform. -It has been found impossible to manufacture. the cutter itself in the first instance so that it will balance and run with all its cutting edges on a cutie around the center of rotation. Any lack of concentricity of the totality of the cutting edges about the rotational axis will causo'ytrouble. A good trimmer can detect a deviation from true running amounting to considerably less than 0.001 inch. The hardening of the cutter generally warps it slightly and besides, the sliaft on which it is placed may be a little out of balance. When the shaft and cutter are rotated at high speeds such as the speed mentioned, the system will tend to balance itself about its own center of gravity, but the cutter, even if perfect in itself, will not run true.

It is necessary then to true the cutter after it has been mounted in the machine, and with reference to its running position and preferably at the speed at which it is to be actually run. This is done by supporting, in some manner, a piece of steel, such as a screwdriver blade, or a piece of corundum or carborundum, close to the rotating cutter, and holding it so that the high teeth will he nicked by it as they rotate, and then grinding back the front faces of the nicked teeth to the bottoms of the nicks. It is of course necessary that the object used to nick the teeth be held with the greatest care and steadiness.

It is the object of my invention to provide a simple and cheaply manufactured means of dealing with the above described problems, and to make the machine convenient and easy to handle. I accomplish this by providing a rest for the truing tool in convenient position to be used in the truing operation. In the embodiment shown in the drawings I have united the finger guard and tool rest in one element, thereby providing an additional steady rest for the hand during the truing operation. This element is shown adjustable so that the rest may be put in the most advantageous working position and may he moved out of the way when no longer needed, keeping the guard in its Patented Dec. 3, 1918 in the normal use of the machine.

y the screw,

normal relation to the cutter, for use in the trimming operation.

Theseand other features of the invention comprising various combinations and arrangen'ients of parts will be best understood and appreciated from the following description of a preferred embodiment thereof selected for purposes of illustration and shown in the accompanying drawings in which,

Figure 1 chine,

Fig. 2 is a-perspective and cutter, and

Fig. 3 shows the procedure used in truing the cutter.

The cutter shaft 10 is rotated in hearings in the head 12 by the pulley 14. A cylinder 16 is mounted on a. strap 18 which is fastened to the head by an oil cup 20, screwing through a hole in its owl. The cylinder is supported SllbSllflUtlullV concentric with the shaft 10, on the projecting end of which the cutter 22 is mounted, the shaft being of considerably less diameter than the inside of the cylinder.

The cylinder carries the sleeve 24, which is slidable longitudinally and tangentially in the'cylinder and on the shaft, and is clamped in adjusted position by a screw 26. It is therefore normally stationary relative to the shaft, and the shaft balancing prob lem is not affected by its presence or adjustment.

The outer end of the sleeve is flanged, a part of the flange, 28, being of slightly greater radius than the ends of the teeth at the base of the cutter. ,The remainder of the flange 30, is shown of greater radius, and carries a projection 32, parallel to the shaft and of length about equal to the height of the cutter. When the cutter has been securely mounted on the shaft, the screw 26 is loosened, the sleeve 24 is turned over into the osition shown in Fig. 3 and fastened there and the machine is started and run up to speed. The broadened flange 30 is then under the cutter and the projection 32 is in position to act as a rest for the truing tool 34. This tool is held by the operator, who may rest his finger on the' flange 30 to steady his hand, and is carefully advanced until the high teeth strike the tool in their rapid rotation. The machine is then stopped and these teeth are ground down to the bot toms of the nicks. The cutter .will then be true when the shaft is running. When the truing of the cutter has been finished the sleeve is turned up to the position of Fig. ,1 and the narrower portion 28 of the flange will serve as a guard for the operators fini fir grinding of the cutter will be done preferably is a side elevation of the maof the sleeve, shaft,

' In a machine adapted for that operation, the

cuttci oulng removed from the trimming machine for that purpose. It is of course neccssary that the cutter be replaced on the trimming machine shaft in exactly the same relative position it occupied when it was niclu-d, in order not to vitiatc the result of the trimming operation.

I have thus provided a sleeve which fulfils all the requirements of the sleeve heretofore used, which will not throw the shaft out of balance and which will serve as a guard and a steady rest during the truing operation.

Having described the invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a machine of the class described, a cutter carrying shaft adapted for hi h-speed rotation, and a sleeve surrounding tie shaft carrying a guard constructed and arranged to prevent t e operators hand from coming into contact with a side of the cutter, while leaving substantially the entire periphery of the cutter exposed, said sleeve carrying also a rest for a truing tool which extends substantially across the face of the cutter.

2. In a machine of the class described, a shaft carrying a cutter, and a stationary member adjustable relative to the cutter, carrying a guard constructed and arranged to prevent the operators hand from coming into contact with a side of the cutter while leaving substantially the entire periphery of the cutter expose anda rest extending across the width of the cutter constructed and arranged to support a truing tool.

3. In a machine of the class described, a shaft, carrying a cutter, and a stationary sleeve encircling the shaft having a uard for the cutter while leaving substantial y the entire periphery of the cutter exposed, and a rest having a surface substantially parallel to the axis and opposite the face of the cutter to support a truing tool.

4. In a machine of the class described, a shaft adapted for high-speed rotation carrying' a cutter, and a statlonary sleeve enci1= cling the shaft having a guard for the cutter and a rest for a truin'g tool, the sleeve being adjustable around the shaft whereby the rest may be placed in inoperative position.

5. In a machine of the class described,a shaft adapted for high-speed rotation carrying a cutter, a stationary sleeve encircling the shaft and having its end constructed and arranged to act as a guard for preventing the operators hand from coming into contact with a side of the cutter while leaving substantially the entire periphery. of the" cutter exposed, and a steady rest proi'ecting from said sleeve, substantially.paralle to the axis of and opposite the face of the cutter" 'm act as a support for a truing tool..

" 1,aee,aao a 6. In a machine of the class described, a to place the rest in operative or inoperative shaft ada ted for high-speed rotation earry position, but the guard being in Opel-fil ing a cut er, a stationary sleeve encircling position at all times. the shaft and having its end constructed and In testimony whereof I have signed my 5 arranged to act as a guard for the cutter, and name to this specification.

a steady rest projecting from said sleeve, the sleeve being adjusta e around the shaft HARRY T. BLACKWELL. 

